NEOPLASTIC DISEASES IN CHICKENS 27 



nerve branch between the spinal cord and sympathetic ganglion which arises 

 at the level of the fifth thoracic vertebra was distinctly enlarged at a point an- 

 terior to the vertebral articulation of the fifth rib. The enlarged nerve joined an 

 irregular firm mass situated in the region of the anterior mesenteric and coeliac 

 nerve plexuses. Nerve radicals extending from the tumor mass were normal. 

 The posterior portion of the left ischiadic nerve was enlarged to a diameter of 

 7 mm. in the femoral region. The enlargement extended for a distance of 3.5 cm. 

 along the course of the nerve. The histology of the enlargements in both loca- 

 tions was similar and consisted of a mass of proliferating fibroblastic cells tending 

 to form whorls and fissures (Plate I, Figure 2). Except for a cystic thyroid gland 

 no other pathology was found. 



A type of connecti\e tissue tumor situated either in or about nerves was a 

 common characteristic of the neurogenic sarcomas. In two cases the tumor was 

 single and aflfected dorsal root ganglia in the brachial region. In one case the tumor 

 was found in two widely separated nerve trunks. In the remaining two cases 

 the tumors were not localized but rather tended to be widespread and to in- 

 filtrate the adjacent tissues as well as the nerves which they surrounded. The 

 association of one case with lymphocytoma and of another case with lesions of 

 fowl paralysis has been regarded as merely incidental and without significance. 

 The fibroblastic elements of the tumors appear to be of low malignancy and in 

 most of the cases ha\e a distinct tendency to form a whorl-like arrangement. 

 Jackson (13) has described a case of multiple neurofibromatosis in a chicken. 

 The histological appearance of the neurofibromas of Jackson's case is similar to 

 that observed in most of the cases of this series. The pathogenesis of the tumors 

 classified as neurogenic sarcoma is obscure. Most if not all may have had their 

 origin from the fibrous sheath covering the nerves. The origin of the neoplasia 

 could not be ascertained in Cases T 97 and T 288, in which the tumor was wide- 

 spread and involved several nerves in a localized area along with adjacent tissue. 

 Although these two cases differ in this respect from others of the group their 

 histology was similar. 



Selection of a term to be applied to these tumors was difficult. Neurogenic 

 sarcomas encountered in human pathology often show a palisading of nuclei 

 which was absent from these cases. The tendency for the tumor cells to form 

 whorls was similar to that noted in multiple neurofibromatosis, although the 

 localization and, in two cases, invasiveness of adjacent tissue are features not 

 noted in multiple neurofibromatosis. For the present it seems logical to classify 

 the tumors as neurogenic sarcoma with the hope that future study of a larger 

 group of similar cases will clarify their identity. 



Epithelioblastoma 



Although this section is headed epithelioblastoma, two types of neoplasia 

 falling under this classification are discussed separately. These are hepatoma 

 and cholangioma. 



Epithelioblastoma was found in 24 cases. The tumor was believed to have 

 originated fron: the ovary in 8 cases, from the liver in 7, from the pancreas in 

 5, and from the gizzard, esophagus, skin, and thyroid in the remaining 4 cases. 

 The salient data on 17 of the cases are set forth in Table 15. 



The neoplasms originating in the ovary were with one exception of an un- 

 differentiated type. One adenocarcinoma was found. In four instances the 

 tumors were represented by small pedunculated masses attached to the ovary. 

 These are listed in Table 15 as solid adenomas. Although they did not show the 

 acinar arrangement typical of adenomas, they seemed to be benign tumors of 

 undifferentiated epithelial cells (Plate IX, Figure 3). The remainder affected the 

 entire organ. In one case the ovarian mass weighed 177 grams. Five of the 

 tumors were confined to the ovary and the other three had spread by extension 



